Yttrium-90 Anti-CD25-BEAM-Conditioning for Autologous Hematopoietic Cell Transplantation in Peripheral T Cell Lymphoma

Peripheral T cell lymphomas (PTCL) have a poor prognosis with current treatments. High-dose chemotherapy followed by autologous hematopoietic cell transplant (AHCT) is used as a consolidation strategy after achieving clinical remission with first-line therapy, as well as in chemosensitive relapse if allogeneic transplant is not an option. CD25 is a targetable protein often highly expressed in PTCL. In this phase 1 clinical trial, we tested the addition of beta-emitting 90Y-labeled chimeric anti-CD25 basiliximab (aTac) to BEAM (carmustine, etoposide, cytarabine, melphalan) as conditioning for AHCT in patients with PTCL. Twenty-three AHCT-eligible patients were enrolled, and 20 received therapeutic 90Y-aTac-BEAM AHCT. Radiation doses of 0.4, 0.5 and 0.6 mCi/kg were tested. With no observed dose-limiting toxicities, 0.6 mCi/kg was deemed the recommended phase 2 dose. The most prevalent adverse effect, grade 2 mucositis, was experienced by 80% of patients. As of this report, 6 (30%) of the treated patients had died, 5 due to progressive disease and 1 due to multiple organ failure median time of death 17 mo (range: 9-21 mo) post-AHCT. Median follow-up was 24 mo (range: 9-26 mo) overall and 24 mo (range: 13-26 mo) for surviving patients. For patients who received therapeutic 90Y-aTac-BEAM AHCT, the 2-year progression-free and overall survival were 59% (95% CI: 34-77%) and 68% (95% CI: 42-84%), respectively. 90Y-aTac-BEAM appears to be safe as an AHCT conditioning regimen for PTCL, with no increased toxicity over the toxicities historically seen with BEAM alone in this patient population. This trial was registered at www.clinicaltrials.gov as # NCT02342782.